Chronic and acute wounds, including pressure ulcers, diabetic wounds, and burns, present significant challenges to the health care industry. Patient care providers are actively seeking methods, devices, and systems for treating such wounds at a lower cost and with greater efficacy.
Conventional treatments for chronic wounds typically include either negative pressure therapy and/or hyperbaric oxygen therapy.
Negative pressure therapy is the controlled application of sub-atmospheric pressure to a wound using a therapy unit, such as a vacuum or suction device, to expose the wound to negative pressure to help promote wound healing. The wound is typically covered to facilitate the application of negative pressure and suction at the wound area. Various types of resilient, open cell foam surface dressings are typically sealed within an adhesive drape to provide the sub-atmospheric pressure at the wound site. Exudates are drained from the wound site and typically directed to a canister that stores the fluids and/or infectious material until properly disposed. Negative pressure wound therapy is often prescribed for chronic and acute wound types such as diabetic wounds, pressure ulcers, abdominal wounds, trauma wounds, various burns, flaps and grafts. However, negative pressure therapy may be less effective on patients having vascular disorders, such as diabetes, because negative pressure therapy can create a hypoxic environment at the wound. In current hospital settings, portable vacuum pumps are often rented or purchased for the purpose of providing negative pressure therapy. This can significantly increase the cumulative costs of providing wound care.
Hyperbaric oxygen therapy is the controlled application of oxygen to a wound at greater-than-atmospheric pressures. Oxygen is typically required for all new cell growth. Chronic or non-healing wounds tend to exhibit low oxygen tensions, or tend to be ischemic. A wound can become dormant if the amount of poorly oxygenated wound tissue reaches a critical mass. In this state, the body may no longer recognize the need to heal the affected area, thereby exacerbating the lack of oxygen in the wound and impairing healing of the wound by the body. Oxygen therapy is particularly useful for patients with poor circulation. The oxygen helps to kill bacteria and when applied to an open wound at a hyperbaric level, the oxygen is dissolved into the wound and absorbed by the surface wound tissue. The cells of the wound tissue that absorb the oxygen will begin metabolic activity in response to the increased oxygen tension. When the oxygen source is removed, the previously active cells request more oxygen from the body. The body responds by beginning to form new blood cells, and thus, starting the healing process. Accordingly, when delivered to a wound site under hyperbaric conditions, oxygen may act as a primary wound treatment fluid
Typically, hyperbaric oxygen therapy is delivered by placing the patient in a hyperbaric chamber that encompasses the full body of the patient or an entire extremity, such as a leg or an arm. Such chambers are problematic due to their lack of portability, the difficulty in sterilization of the chambers between patients, and the potential adverse effects of breathing oxygen at hyperbaric pressure. Preferably, hyperbaric oxygen treatment should be localized at the wound site rather than applied to the patient's entire body or extremity.
While both negative pressure and hyperbaric oxygen therapies are each believed to be effective when administered as separate wound care treatments, many patients may benefit from a treatment protocol incorporating both negative pressure and hyperbaric oxygen therapies. Because existing hyperbaric oxygen treatment is typically performed in a hyperbaric chamber, switching between negative pressure therapy and hyperbaric oxygen therapy is time-consuming. Before entering a hyperbaric oxygen chamber, a patient must first be disconnected from the negative therapy device. Thee negative pressure therapy dressing, which typically includes packing materials, a drain, tubing, and sealing material, must then be removed. Following hyperbaric oxygen treatment, a new negative pressure dressing would have to be applied. These procedures are wasteful and time-consuming, making it difficult, if not impossible, to alternate between negative pressure therapy and hyperbaric oxygen therapy every few minutes or less.
More recently, wound care systems and methods have been developed that combine negative and positive pressure (e.g. hyperbaric oxygen) wound treatment therapies. Such methods and systems are described, for example, in U.S. Pat. No. 7,648,488 issued Jan. 19, 2010; U.S. Pat. No. 8,357,130 issued Jan. 22, 2013; U.S. Patent Publication No. 2008/0140029; and U.S. Patent Publication No. 2010/0121287; all of which are hereby incorporated in their entirety by reference.
Wound care treatment may be further enhanced by deactivating pathogenic microorganisms within the wound environment and physically removing the deactivated microorganisms and other toxins from the wound site. While antibiotics and other drugs may be effective in destroying bacteria and other pathogens, their activity may disrupt the cell walls of the microorganisms, thereby releasing harmful enzymes and other toxins into the wound environment. These harmful enzymes and toxins must be removed or they may become cytotoxic.
It is also known that when planktonic, free floating, individual microorganisms, like bacteria, attach to a surface and gather in groups within a wound environment, they may produce an extra-cellular matrix called a biofilm. Biofilms are held together and protected by a matrix of excreted polymeric compounds called EPS (exopolysacchride). Biofilms provide a protective environment for microorganisms that exist within the biofilm mass and a level of immunity from antibiotic treatments, except in doses that would be fatal to the patient. Consequently, biofilm microorganisms are not affected by the body's own infection-resistance mechanisms. In addition, bacterial biofilms may impair cutaneous wound healing and reduce topical antibacterial efficiency in healing or treating infected skin wounds.
Hypochlorous acid (HOCI) is an active component found in the human immune system as a natural defense against infection, and thus kills bacteria, fungi and viruses without creating mechanisms for drug resistance. Hypochlorous acid compounds can be a safe, fast acting, broad spectrum antimicrobial for topical application, effective against all groups of hydrophobic, hydrophilic, gram-negative and gram-positive bacteria, and yeast, including pseudomonas aeruginosa, Staphylococcus aureus, and multi-drug resistant organisms like methicillin resistant staphylococcus aureus (MRSA), and vancomycin resistant enterococci (VRE). In addition, hypochlorous acid compounds rapidly penetrate and disrupt biofilm and eradicate the pathogens, the major factor that inhibits wound healing. Unlike most antibiotics, which can take many hours to work, hypochlorous acid compounds, even at small doses, can help eradicate bacteria, fungi and viruses in minutes. When applied topically within a wound environment, hypochlorous acid compounds immediately disrupt and eradicate the bio-film, which surrounds and deactivates a broad spectrum of pathogenic microorganisms. Hypochlorous acid generally controls the tissue bacterial bio-burden without inhibiting the wound healing process and is also commonly associated with improved wound closure. Accordingly, a wound treatment therapy using a stabilized hypochlorous acid compound has recently been disclosed in U.S. Patent Publication No. 2012/0328680, the entirety of which is hereby incorporated by reference.
What is needed, then, is an apparatus that can effectively, and at low cost, operate in multiple treatment modes to deliver one or more different wound therapies to a wound site.